The present invention relates to a pneumatic nail gun that has a chamber communicating with an interior of a cylinder and the air in the cylinder is pushed into the chamber when ejecting a nail. The air in the chamber pushes the piston back quickly when the trigger is released.
A conventional pneumatic nail gun is shown in FIG. 1 and generally includes a cylinder 241 received in the body of the gun, a handle 1 with a main passage 11 connected the body, and a trigger valve 50 movably received in a space 12 of the handle 1. The cylinder 241 has a pushing member 22 movably connected to an end thereof and a spring 21 is engaged between the pushing member 22 and an end cap 2 which is fixed to the body of the gun. The pushing member 22 movably seals an end of the cylinder 241 by the spring 21. The main passage 11 communicates with a space defined between the cylinder 241 and the pushing member 22 and a hole 13 defined through a wall of the handle 1 so as to communicate the main passage 11 and the space 12. A tube 3 is connected between the space 12 and the end cap 2, and a first passage 20 is defined in the end cap 2 and communicates with a space between the end cap 2 and the pushing member 22. The pushing member 22 is pushed by the spring 21 and the air pressurized coming from the first passage 20 so that the piston 25 is located at the ready-to-fire position as shown.
Referring to FIGS. 2 and 3, when the safety member 55 is pushed and the trigger 5 is pulled, the trigger valve 50 is moved to seal the hole 13 so that the pressurized air in the space between the end cap 2 and the pushing member 22 disappeared such that the pushing member 22 is pushed toward the end cap 2 and removed away from the end of the cylinder 241 by the pressurized air coming through slots 230 of a base 23 mounted to the cylinder 241. The pressurized air enters into the cylinder 241 to push the piston 25 from the gap resulted from the movement of the pushing member 22 so that a nail is ejected by the ejection plate connected to the piston 25. The air in the cylinder 241 is forced to be released into a space 100 between the cylinder 241 and the in side of the body of the gun via holes 240 defined through the cylinder 241.
Referring to FIG. 4, when releasing the trigger 5, the pressurized air reaches the space between the pushing member 22 and the end cap 2 again via the first passage 20 so that the pushing member 22 is pushed to seal the end of the cylinder 241 again by the force of the spring 21 and the pressurized air. The piston 25 is pushed back to its ready-to-fire position by the air in the space 100 via the holes 240 of the cylinder 241.
The size of the cylinder is limited by the diameter of the body of the gun and if larger nails are to be ejected, a bigger body of the gun is required to receive a larger cylinder, and this makes the whole nail gun to be bulky and heavy. Besides, the structure is so complicated and involves too many parts which are not convenient to be maintained.
The present invention intends to provide a pneumatic gun that guides the air to be released when pulling the trigger to push the piston back more quickly.
The present invention relates to a pneumatic nail gun and comprises a cylinder in a body of the gun and an end cap is fixed to connected a rear end of the body. A barrel is connected to a front of the body and a piston is movably received in the cylinder. An ejection plate is connected to the piston and movably inserted in the barrel.
A pushing member movably seals a first end of the cylinder and a spring is biased between the pushing member and the end cap. A second passage and a third passage are respectively defined through the end cap. The third passage communicates with a space defined between the cylinder and an inside of the body of the gun. An opening is defined in a second end of the cylinder and in communication with the space between the cylinder and the inside of the body of the gun and an interior of the cylinder.
A handle with a main passage is connected to the body and a trigger valve is received in a space in the handle. A hole is defined through the handle and communicates with the space and the main passage. A tube is located across the main passage and in communication with the second passage. A fourth passage is defined in the handle and communicates with the space.
The primary object of the present invention is to provide a pneumatic nail gun wherein the piston can be moved back to its ready-to-fire position quickly, and the gun allows a larger area piston operated in a compact body of the gun.